Weighted time-based global hierarchical path planning in dynamic environment

A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid- or graph-based modeling is performed and the environment is divided into a set of grids or nodes. Then two time-based features of time interval and time cost are presented. The time intervals for each grid are built, during each interval the condition of the grid remains stable, and a time cost of passing through the grid is defined and assigned to each interval. Furthermore, the weight is introduced for taking both time and distance into consideration, and thus a sequence ofmultiscale paths with total time cost can be achieved. Experimental results show that the proposed method can handle the complex dynamic environment, obtain the global time optimal path and has the potential to be applied to the autonomous robot naviga- tion and traffic environment.     

Adaptive progressive download based on the MPEG-4 file format

In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the "moov" box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Re1-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.     

弱可串行分布式实时事务并发控制

Most of the proposed concurrency control protocols for real-time database systems are based on serializability theorem.Owing to the unique characteristics of real-time database applications and the importance of satisfying the timing constraints of transactions,serializability is too strong as a correctness criterion and not suitable for real-time databases in most cases.On the other hand,relaxed serializability including epsilon-serializability and similarity-serializability can allow more real-time transactions to satisfy their timing constraints,but database consistency may be sacrificed to some extent.We thus propose the use of weak serializability(WSR)that is more relaxed than conflicting serializability while database consistency is maintained.In this paper,we first formally define the new notion of correctness called weak serializability.After the necessary and sufficient conditions for weak serializability are shown,corresponding concurrency control protocol WDHP(weak serializable distributed high prority protocol)is outlined for distributed real time databases,where a new lock mode called mask lock mode is proposed for simplifying the condition of global consistency.Finally,through a series of simulation studies,it is shown that using the new concurrency control protocol the performance of distributed realtime databases can be greatly improved.     

A Case Against the Linguistic Approach to Metaphysics Zeno Vendler’s Project and Beyond

There are two approaches to metaphysics that concern language,the logical and the linguistic. Zeno Vendler,who took the linguistic one,distinguished with transformational techniques between two semantic categories,namely fact and event,and regarded them as corresponding respectively to a metaphysical category of beings. In doing this he presupposed that independent semantic categories could be sorted out,and corresponding categories of beings that are independent of language can be derived. But our analysis of Vendler’s case shows that it is not semantic categories but grammar that functions in differentiating event and fact. At least some semantic categories could not be separated from grammar,and this casts doubt on the linguistic approach to metaphysics. If semantic categories are not independent of grammar,we could not derive metaphysics from linguistic study.     

A Comparative Study of Metonymy and Synecdoche

Among the modern rhetorical devices,metonymy and synecdoche are two important figures of speech,which are analogous to each other for both use the name of one thing for that of something else.That is to say,both of the rhetorical devices involve substitution.Thus the two concepts are confusing.Metonymy emphasizes on using the name of one thing for that of something else with which it is associated.Synecdoche is a figure of speech in which a part is used for a whole,an individual for a class,a material for a thing,or the reverse of any of these.By making a comparative study of these two through the connotation and category,the author summarizes that:they are two independent figures of speech.     

Mathematical modelling of translational motion of rail-guided cart with suspended payload

In this paper modelling of the translational motion of transportation rail-guided cart with rope suspended payload is considered. The linearly moving cart,driven by a travel mechanism,is modelled as a discrete six degrees of freedom (DOF) dynamic system. The hoisting mechanism for lowering and lifting the payload is considered and is included in the dynamic model as one DOF system. Differential equations of motion of the cart elements are derived using Lagrangian dynamics and are solved for a set of real-life constant parameters of the cart. A two-sided interaction was observed between the swinging payload and the travel mechanism. Results for kinematical and force parameters of the system are obtained. A verification of the proposed model was conducted.     

Numerical Modeling of the Performance of R22 and R290 in Adiabatic Capillary Tubes Considering Metastable Two-Phase Region——Flow Characteristics and Parametric Analysis of R22 and R290

Characteristics of R22 and its new alternative refrigerant R200 flowing through adiabatic capillary tubes are investigated based on the homogeneous model. Extensive flow variables along tube length such as pressure, temperature, viscosity, velocity. Reynolds number, friction factor and vapor quality etc are compared between the two fluids under the same operating condition. Two cases are considered, namely, either the same tube length or the same mass flow rate as inlet condition. The results show that the mass flow rate in the capillary tube of R290 is 40% lower than that of R22 due to the differences of physical properties between the two fluids. Further. a parametric analysis is performed and it appears that effects of geometric and thermodynamic parameters on mass flow rate of R290 are weaker than that of R22. When the condensing temperature is increased from 40℃ to 50℃ C. the mass flow rate for R22 is increased by 16%. while the increasing rate for R290 is 13%.     

Hardware architecture for RSA cryptography based on residue number system

A parallel architecture for efficient hardware implementation of Rivest Shamir Adleman(RSA) cryptography is proposed.Residue number system(RNS) is introduced to realize high parallelism,thus all the elements under the same base are independent of each other and can be computed in parallel.Moreover,a simple and fast base transformation is used to achieve RNS Montgomery modular multiplication algorithm,which facilitates hardware implementation.Based on transport triggered architecture(TTA),the proposed architecture is designed to evaluate the performance and feasibility of the algorithm.With these optimizations,a decryption rate of 106 kbps can be achieved for 1 024-b RSA at the frequency of 100 MHz.     

Wireless Base Stations:Any Scale,Any Terrain

It becomes faster and faster of the telecommunication development with the wireless technology evaluation.The communication between each other becomes more and more popular and widely,it already is one indispensable part of our life.The wireless coverage is the key parts to supply service for subscribers.How to build the wireless site in different scenarios,such as urban,suburban,high railway,remote areas,etc? It will be discussed and proposed in this paper.Our vision is that to make better service for the general radio service for the people.     

Highly parallel implementation of sub-pixel interpolation for AVS HDTV decoder

In this paper, we propose an effective VLS1 architecture of sub-pixel interpolation for motion compensation in the AVS HDTV decoder. To utilize the similar arithmetical operations of 15 luma sub-pixel positions, three types of interpolation filters are proposed. A simplified multiplier is presented due to the limited range of input in the chroma interpolation process. To improve the processing throughput, a parallel and pipelined computing architecture is adopted. The simulation results show that the proposed hardware implementation can satisfy the real-time constraint for the AVS HDTV （1 920× 1 088） 30 fps decoder by operating at 108 MHz with 38.18k logic gates. Meanwhile, it costs only 216 cycles to accomplish one macroblock, which means the B frame sub-pixel interpolation can be realized by using only one set of the proposed architecture under real-time constraints.     

Analytical solution for 1D consolidation of unsaturated soil with mixed boundary condition

Based on consolidation equations proposed for unsaturated soil, an analytical solution for 1D consolidation of an unsaturated single-layer soil with nonhomogeneous mixed boundary condition is developed. The mixed boundary condition can be used for special applications, such as tests occur in laboratory. The analytical solution is obtained by assuming all material parameters remain constant during consolidation. In the derivation of the analytical solution, the nonhomogeneous boundary condition is first transformed into a homogeneous boundary condition. Then, the eigenfunction and eigenvalue are derived according to the consolidation equations and the new boundary condition. Finally, using the method of undetermined coefficients and the orthogonal relation of the eigenfunction, the analytical solution for the new boundary condition is obtained. The present method is applicable to various types of boundary conditions. Several numerical examples are provided to investigate the consolidation behavior of an unsaturated single-layer soil with mixed boundary condition.     

On some projectively flat polynomial （α,β）-metrics

In this paper, we consider some polynomial (α,β)-metrics, and discuss the sufficient and necessary conditions for a Finsler metric in the form F=α a1β a2β2/α a4β4/α3 to be projectively flat, where ai (i=1,2,4) are constants with a1≠0, α is a Riemannian metric and β is a 1-form. By analyzing the geodesic coefficients and the divisibility of certain polynomials, we obtain that there are only five projectively flat cases for metrics of this type. This gives a classification for such kind of Finsler metrics.     

Sliding-mode observers for systems with unknown inputs and measurement disturbances

The method to design sliding-mode observers for systems with unknown inputs and measurement disturbances is presented in the paper. An augmented system is constructed by viewing the measurement disturbances as unknow inputs. For such an augmented system, the so-called observer matching condition is not satisfied. Based on the construction of auxiliary outputs, the observer matching condition may be satisfied. High-order sliding-mode differentiators are developed to obtain the estimates of those unmeasurable variables contained in the auxiliary output vector. Employing the estimate of auxiliary output vector, a sliding-mode observer is designed. The simulation results to a real model show that the proposed method is effective.     

Should Exam Be Stopped?

The exam system has come to be the main topic of modern education.As it plays so important a role in the area of education that it is under much discussion as to its use.People who are for it try to develop this system more;those who are against it believe that such a system should be stopped.Should exam be stopped?In my opinion it should be.Firstly,a number of people think that an exam is the only way to test knowledge,but,in fact,that is not true.A few questions given in an exam could in no…     

Parallel processing architecture of H.264 adaptive deblocking filters

In H.264, computational complexity and memory access of deblocking filters are variable, dependent on video contents. This paper proposes a VLSI architecture of deblocking filters with adaptive dynamic power, which avoids redundant computations and memory accesses by precluding the blocks that can be skipped. The vertical and horizontal edges are simultaneously processed in an advanced scan order to speed up the decoder. As a result, dynamic power of the proposed architecture can be reduced adaptively （up to about 89%） for different videos, and the off-chip memory access is improved when compared to previous designs. Moreover, the processing capability of the proposed architecture is in particular appropriate for real-time deblocking of high-definition television （HDTV, 1920× 1080 pixels/frame, 60 frames/s video signals） video operation at 62 MHz. Using the proposed architecture, power can be reduced by up to about 89% and processing time by from 25% to 81% compared with previous designs.     

Kerr黑洞熵的内禀拓扑结构

In the light of Ф-mapping method and the relationship between entropy and the Euler characteristic, the intrinsic topological structure of entropy of Kerr black holes is studied. From the Ganss-Bonnet-Chem theorem, it is shown that the entropy of Kerr black hole is determined by singularities of the Killing vector field of spacetime. These singularities naturally carry topological numbers, Hopf indices and Brouwer degrees, which can also be viewed as topological quantization of entropy of Kerr black holes. Specific results S = A/4 for non-extreme Kerr black holes and S = 0 for extreme ones are calculated independently by using the above-mentioned methods.     

Netcronym： Translation or Borrowing

Technical advancements have given birth to many netcronyms. This paper analyzes five methods which account for the formation of netcronym: acronym, initial, clipping, blending and homophonic pronunciation. Finally it is proposed that borrowing or transliteration will be the main trend of the translation of netcronyms on the basis of Adaptation Theory.     

On some projectively flat polynomial (α,β)-metrics

In this paper, we consider some polynomial (α,β)-metrics, and discuss the sufficient and necessary conditions for a Finsler metric in the form F=α+α1β+α2β2/α+α4β4/α3 to be projectively flat, where αi (i=1,2,4) are constants with α1≠0, α is a Riemannian metric andβ is a l-form. By analyzing the geodesic coefficients and the divisibility of certain polynomials, we obtain that there are only five projectively flat cases for metrics of this type. This gives a classification for such kind of Finsler metrics.     

Discrete Conley index and bifurcation points

In this paper, a sufficient condition for the existence of bifurcation points for discrete dynamical systems is presented. The relation between two families of systems is further discussed, and a sufficient condition for determining whether they may have the similar bifurcation points is given.     

美国人的时间观

There are two elements in life that Americans dosave carefully: time and labor."Americans are slaves to nothing but theclock, "it has been said. Time is treated as if it were an almost tangible entry. In their language, there are words associated with it: time can be budgeted, saved, wasted, stolen, killed, and cut. Americans also charge for time. It is a precious commodity to them. Many people have a rather acute sense of the shortness of each lifetime. Once the sands have run out of a person' s hourglass, they can not be replaced. They want every minute to count.